This invention relates generally to the initiation of crystallization of a supercooled salt solution; more particularly, it concerns the provision of a protective trigger easily deformable and constructed to initiate such crystallization when the trigger is deformed, and without failure or injury to a plastic container in which the trigger is confined.
Devices of the general type with which the present invention is concerned are described in U.S. Pat. No. 4,077,390; however, such devices have tended to suffer from accidental triggering of crystallization. For example, accidental flexing of the actuator strips described in that patent can initiate unwanted crystallization. Also, the edges of such strips can and do tear the plastic container, causing leakage of the salt solution. This greatly aggravates the user and reduces the practicality and utility of such devices. Also, trigger surfaces can corrode or discolor.